#计算器可以进行基础运算（加、减、乘、除）被除数不为0
first = float(input('请输入第一个数：'))
second = float(input('请输入第二个数：'))
operator =  input('请选择运算符：+ = * /：')
if operator == '+':
    print(first + second)
elif operator == '-':
    print(first - second)
elif operator == '*':
    print(first * second)
elif operator == '/':
    if second ==0:
        print('除数不能为0')
    else:
        print(first/second)